[PATCH AUTOSEL 5.10 08/51] netfilter: ipset: fixes possible oops in mtype_resize

[Sasha Levin]

From: Vasily Averin <v...@virtuozzo.com>

[ Upstream commit 2b33d6ffa9e38f344418976b06057e2fc2aa9e2a ]

currently mtype_resize() can cause oops

        t = ip_set_alloc(htable_size(htable_bits));
        if (!t) {
                ret = -ENOMEM;
                goto out;
        }
        t->hregion = ip_set_alloc(ahash_sizeof_regions(htable_bits));

Increased htable_bits can force htable_size() to return 0.
In own turn ip_set_alloc(0) returns not 0 but ZERO_SIZE_PTR,
so follwoing access to t->hregion should trigger an OOPS.

Signed-off-by: Vasily Averin <v...@virtuozzo.com>
Acked-by: Jozsef Kadlecsik <kad...@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 net/netfilter/ipset/ip_set_hash_gen.h | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_hash_gen.h 
b/net/netfilter/ipset/ip_set_hash_gen.h
index 521e970be4028..8d4a9e0fd723f 100644
--- a/net/netfilter/ipset/ip_set_hash_gen.h
+++ b/net/netfilter/ipset/ip_set_hash_gen.h
@@ -644,7 +644,7 @@ mtype_resize(struct ip_set *set, bool retried)
        struct htype *h = set->data;
        struct htable *t, *orig;
        u8 htable_bits;
-       size_t dsize = set->dsize;
+       size_t hsize, dsize = set->dsize;
 #ifdef IP_SET_HASH_WITH_NETS
        u8 flags;
        struct mtype_elem *tmp;
@@ -668,14 +668,12 @@ mtype_resize(struct ip_set *set, bool retried)
 retry:
        ret = 0;
        htable_bits++;
-       if (!htable_bits) {
-               /* In case we have plenty of memory :-) */
-               pr_warn("Cannot increase the hashsize of set %s further\n",
-                       set->name);
-               ret = -IPSET_ERR_HASH_FULL;
-               goto out;
-       }
-       t = ip_set_alloc(htable_size(htable_bits));
+       if (!htable_bits)
+               goto hbwarn;
+       hsize = htable_size(htable_bits);
+       if (!hsize)
+               goto hbwarn;
+       t = ip_set_alloc(hsize);
        if (!t) {
                ret = -ENOMEM;
                goto out;
@@ -817,6 +815,12 @@ mtype_resize(struct ip_set *set, bool retried)
        if (ret == -EAGAIN)
                goto retry;
        goto out;
+
+hbwarn:
+       /* In case we have plenty of memory :-) */
+       pr_warn("Cannot increase the hashsize of set %s further\n", set->name);
+       ret = -IPSET_ERR_HASH_FULL;
+       goto out;
 }
 
 /* Get the current number of elements and ext_size in the set  */
-- 
2.27.0